You know that room where someone was pushing down exploding boxes at you and you find a cyborg assassin carrying a quest item. The elevator is broken. Is it possible to get up to the platform there?

no.

So who was pushing those boxes?

So apparently you can get up there using psi barrier as a platform, but there's nothing there.

that

Please define.. in my case, I built in a cold store under my house (root cellar)

I live in New England. The room, which did involve annoying zoning, did ultimately work. I made sure it was north/northeast in my basement. It will store vegetation I intend to grow/store for the foreseeable future.

To give you a better answer... where are you planning to build? (Growing zone wise...)